The comprehensive Cancer Data Management System (CDMS) is being developed and evaluated in the department of Medical Oncology at University Hospital, Boston. The objective of the project is to overcome the deficiencies of traditional medical records and improve patient care for the cancer patient while facilitating clinical research studies. The system operates on a PDP 11 computer under the MUMPS Standard operating system. Detailed but essential medical information is computer-accessible, via computer terminals in the clinic, on the ward, and in the oncology clinical offices. A computer-generated paper medical record is used instead of the traditional paper medical record. This record contains demographic and administration reports, oncology and general medical summaries, patient management flow sheets, encounter reports for clinic visits to nurses and physicians and outside encounters for such as telephone calls. Hospitalizations are summarized in separate computer reports. Information is collected from patients, nurses, and physicians by both standard and customized computer-generated forms. Additional entry occurs by computer terminal from these same users in certain situations. The computer structures the information collection by cueing clinical staff to provide data based on the nature of the cancer, the treatment, and the nature of any protocol in use. The system supports patient care decisions prescribed by research protocol or generally agreed upon patient care practice. It also monitors patient care data, uncovering potential problems and bringing them to the oncologist's attention. Plans for the transfer of the CDMS to another hospital are underway, which will facilitate the systems evaluation. Evaluation procedures assessing system performance and user acceptance are being developed and will be used both inside and at the other site.